OpenBiome Supports FDA Committee’s Endorsement of RBX2660 and Affirms Continued Access to Investigational Fecal Microbiota Transplantation

Press Release


CAMBRIDGE, MA—On September 22, 2022, OpenBiome was excited to witness a major milestone when the U.S. Food and Drug Administration (FDA) Vaccines and Related Biological Products Advisory Committee (VRBPAC) held an open hearing to review data on the safety and efficacy of RBX2660 (Rebyota)—the first Fecal Microbiota Transplantation (FMT) product to be reviewed by the FDA for possible approval. The VRBPAC voted in favor of the adequacy of both the safety and efficacy data supporting RBX2660 (Rebyota) to reduce the recurrence of C. difficile infections (CDI) in adults 18 years of age and older following antibiotic treatment for recurrent CDI.

OpenBiome congratulates the dedicated team behind RBX2660 for their achievements. The positive endorsement by VRBPAC suggests impending FDA approval for the first FMT product to treat recurrent CDI and is a win for patients, physicians, and the field of microbiome-based therapeutics.

However, even with the potential approval of RBX2660 and other microbiome-based therapeutics in the future, investigational FMT will remain an important treatment option—especially for patient groups who will be ineligible for RBX2660 (e.g. those with fulminant, life-threatening CDI requiring FMT via colonoscopy and pediatric patients). Therefore, OpenBiome will continue to provide safe access to investigational FMT for recurrent CDI in neglected patient populations.

We will also continue to work with the American Gastroenterological Association (AGA) on the FMT patient registry to collect valuable long-term outcomes data to inform clinical practice and improve care for patients who suffer from CDI. This important long-term outcomes data will add to a 5,344-patient cohort study published in 2022, which demonstrated a 78% cure rate across all delivery modalities and CDI types treated with OpenBiome investigational FMT preparations consistent with randomized controlled trials published to-date.

OpenBiome remains committed to distributing investigational FMT preparations under the FDA’s policy of enforcement discretion, which permits the use of investigational FMT treatment for recurrent CDI not responsive to standard therapy. The policy of enforcement discretion has successfully balanced access to treatment and enabling innovation in microbiome therapeutics for CDI, as evidenced by the RBX2660 VRBPAC meeting. We hope the Agency continues to consider the needs— as expressed by several patient and expert participants in the open hearing on September 22, 2022—for timely access to investigational FMT for neglected patient groups suffering with CDI who do not qualify for or fail to respond to RBX2660.

Note: This press release was updated on August 7, 2023



About OpenBiome
OpenBiome accelerates bold discoveries in microbiome science to improve health for all. An independent nonprofit, we catalyze cutting edge research, advance treatment, and expand scientific capacity to unlock the full potential of the human microbiome.

Since our founding at MIT in 2012, we have provided investigational FMT treatments to more than 64,000 patients with recurrent C. difficile infections and supported over 40 studies investigating how the microbiome affects human health. Through OpenBiome’s new flagship program, the Global Microbiome Conservancy (GMbC), we are building and sharing the world’s most globally representative library of microbiome samples and strains to fill critical gaps in microbiome science.

For more information, visit

Scroll To Top